To survive in the dark recesses of the ocean, it helps to have a sharp pair of eyes. And preferably eyes that can see through others' visual deceits. On both counts, the short nose green-eye fish swims above the fray.

Like many deep-sea predators, its eyes are turned upward to scan for prey blocking the light that comes from above. But where another fish might have been fooled by a prey using counterillumination, the short-nose green-eye fish uses its sophisticated peepers (pdf) to break up any bioluminescent shams.

The green fluorescent pigment in the lenses of its eyes acts like a filter, absorbing the sea's ambient deep blue light. Researchers believe this property allows the short-nose green-eye fish to distinguish between the lighter shade of blue given off by bioluminescent creatures and the richer blue of the ocean.